Anselm’s Understanding of God – the difference between contingent and necessary existence • His argument centres on a definition of God as ‘that than which nothing greater can be thought’ - God understood to be the highest sum of all perfections, where nothing could surpass him in any way. • Anselm argues that God must exist because a necessary being cannot fail to exist. Necessary existence is part of the very definition of God. It makes no sense to Anselm to talk of a God who does not exist, because then he would not be God. • For Anselm the existence of God is not something which needs to be demonstrated by evidence (a posteriori), instead we can know simply by considering the concept of God – a priori. The Ontological Argument
Descartes’ understanding of existence as a perfection which God cannot lack. • Descartes believed that people were born with innate ideas – that there are some concepts which are imprinted on our minds from birth and which are universally shared by all humanity. • Amongst these concepts he believed we are born with an understanding of what God is. • We understand God to be the supremely perfect being, with all the perfections as his attributes. • Descartes explained that existence is part of the very essence of God, just as three angles adding up to 180 degrees are part of the essence of a triangle and a valley is part of the essence of a mountain. • If God has all perfections, and existence is a perfection, God therefore must exist. Descartes goes on to say that as God is perfect, he must be unchanging and so he must always have existed and will always continue to exist for eternity. The Ontological Argument
Gaunilo’s Criticisms of Ontological Arguments Gaunilo’s Example • Responded to Anselm, ‘On behalf of the fool’. • Writes from a Christian perspective but believed that Anselm’s writing was not logical and therefore needed to be refuted. • Doesn’t argue for the existence of the most excellent island – instead uses this example to show that we cannot bring something into existence just by defining it as superlative. • Suppose, however, he then goes on to say: you cannot doubt this this island…. Actually exists … .If I accepted the argument, I do not know whom I would regard as the greater fool, me for accepting it or him for supposing that he had proved the existence of this island with any kind of certainty.
Anselm’s Response to Gaunilo • Anselm was impressed with Gaunilo’s argument, and included it in later versions of his own book, along with his reply: • Anselm argued that although Gaunilo was right in the case of an island, the same objections did not work when the argument was used of God: • An island has contingent existence • God’s existence is necessary • The Ontological Argument works only when applied to God because of the uniqueness of God and the unique way in which he exists.
Aquinas’ critiques of Anselm • Aquinas argued against Anselm even though he was himself convinced of the existence of God himself: • God’s existence cannot be regarded as self-evident: • Aquinas also questioned whether everyone would accept Anselm’s definition of God as ‘that than which nothing greater can be thought.’ Although we can approach an understanding and awareness of God – he will always remain unknowable to the finite human mind. • He argued instead that there had to be more than just a definition in order to show the existence of God – it was necessary to provide firm evidence. • Truth does not exist • We can see that this is a nonsensical statement because no one accept the truth of ‘truth does not exist’ without contradicting themselves. • There is no God • It is not impossible to have a mental concept of the non-existence of God, because people quite clearly manage to do so.
Kant’s Critique of Ontological Arguments • Kant argued that ‘existence is not a predicate’. • Existence is not a characteristic or an attribute of something (like green, tall, round, sharp etc.) • When we say something ‘exists’ we are not actually adding anything to our identification of an object, instead that this concept has been actualised in real life. • When we think of God (whether using Anselm or Descartes definition) we are thinking of a concept – whether or not that concept is actualised is an issue – but not an issue that can be resolved simply by adding ‘existence’ to the different predicates we are ascribing to our concept.
Malcolm’s modern Ontological Argument • Malcolm accepted Kant’s critique of Ontological Arguments. • Still held that the idea of necessary existence could form the basis of a successful Ontological Argument. • Could be counter-argued – there are lots of things that do not exist but yet are not impossible. • Malcolm’s argument depends on our acceptance that God’s existence is not the same as other kinds of existence.
Plantinga’s modern Ontological Argument • Plantinga uses something called ‘modal logic’ which considers not just what exists and occurs in the world we have, but also what could exist or could occur in a possible world out of an infinite number of possibilities. • Uses this method to try to make sense of what is self-contradictory, possible or necessary in the actual world that we live in.